Early removal of central venous catheter in patients with candidemia does not improve outcome: analysis of 842 patients from 2 randomized clinical trials

BACKGROUND

Patients with candidemia frequently have a central venous catheter (CVC) in place, and its early removal is considered the standard of care.

METHODS

We performed a subgroup analysis of 2 phase III, multicenter, double-blind, randomized, controlled trials of candidemia to examine the effects of early CVC removal (within 24 or 48 h after treatment initiation) on the outcomes of 842 patients with candidemia. Inclusion criteria were candidemia, age >16 years, CVC at diagnosis, and receipt of 1 dose of the study drug. Six outcomes were evaluated: treatment success, rates of persistent and recurrent candidemia, time to mycological eradication, and survival at 28 and 42 days. Univariate and multivariate analyses were performed, controlling for potential confounders.

RESULTS

In univariate analysis, early CVC removal did not improve time to mycological eradication or rates of persistent or recurrent candidemia but was associated with better treatment success and survival. These benefits were lost in multivariate analysis, which failed to show any beneficial effect of early CVC removal on all 6 outcomes and identified Acute Physiology and Chronic Health Evaluation II score, older age, and persistent neutropenia as the most significant variables. Our findings were consistent across all outcomes and time points (removal within 24 or 48 h and survival at 28 and 42 days). The median time to eradication of candidemia was similar between the 2 study groups.

CONCLUSIONS

In this cohort of 842 adults with candidemia followed up prospectively, early CVC removal was not associated with any clinical benefit. These findings suggest an evidence-based re-evaluation of current treatment recommendations.

Safety and pharmacokinetics of repeat-dose micafungin in young infants

Given the risk of central nervous system infection, relatively high weight-based echinocandin dosages may be required for the successful treatment of invasive candidiasis and candidemia in young infants. This open-label study assessed the safety and pharmacokinetics (PK) of micafungin in 13 young infants (>48 h and <120 days of life) with suspected candidemia or invasive candidiasis. Infants of body weight > or =1,000 and <1,000 g received 7 and 10 mg/kg/day, respectively, for a minimum of 4-5 days. In the 7-mg/kg/day group, the mean baseline weight and gestational age were 2,101 g and 30 weeks, respectively; in the 10-mg/kg/day group, they were 688 g and 25 weeks, respectively. The median pharmacokinetic values for the 7- and 10-mg/kg/day groups, respectively, were as follows: area under the concentration-time curve from 0 to 24 h (AUC(0-24)), 258.1 and 291.2 microg x h/ml; clearance at steady state adjusted for body weight, 0.45 and 0.57 ml/min/kg; maximum plasma concentration, 23.3 and 24.9 micro g/ml; and volume of distribution at steady state adjusted for body weight, 341.4 and 542.8 ml/kg. No deaths or discontinuations from treatment occurred. These data suggest that micafungin dosages of 7 and 10 mg/kg/day are well tolerated and provide exposure levels that have been shown (in animal models) to be adequate for central nervous system coverage.

Micafungin versus Caspofungin for Treatment of Candidemia and Other Forms of Invasive Candidiasis

BACKGROUND

Invasive candidiasis is an important cause of morbidity and mortality among patients with health care-associated infection. The echinocandins have potent fungicidal activity against most Candida species, but there are few data comparing the safety and efficacy of echinocandins in the treatment of invasive candidiasis.

METHODS

This was an international, randomized, double-blind trial comparing micafungin (100 mg daily) and micafungin (150 mg daily) with a standard dosage of caspofungin (70 mg followed by 50 mg daily) in adults with candidemia and other forms of invasive candidiasis. The primary end point was treatment success, defined as clinical and mycological success at the end of blinded intravenous therapy.

RESULTS

A total of 595 patients were randomized to one the treatment groups and received at least 1 dose of study drug. In the modified intent-to-treat population, 191 patients were assigned to the micafungin 100 mg group, 199 to the micafungin 150 mg group, and 188 to the caspofungin group. Demographic characteristics and underlying disorders were comparable across the groups. Approximately 85% of patients had candidemia; the remainder had noncandidemic invasive candidiasis. At the end of blinded intravenous therapy, treatment was considered successful for 76.4% of patients in the micafungin 100 mg group, 71.4% in the micafungin 150 mg group, and 72.3% in the caspofungin group. The median time to culture negativity was 2 days in the micafungin 100 mg group and the caspofungin group, compared with 3 days in the micafungin 150 mg groups. There were no significant differences in mortality, relapsing and emergent infections, or adverse events between the study arms.

CONCLUSIONS

Dosages of micafungin 100 mg daily and 150 mg daily were noninferior to a standard dosage of caspofungin for the treatment of candidemia and other forms of invasive candidiasis.

Population pharmacokinetics of micafungin in pediatric patients and implications for antifungal dosing

The echinocandins potentially have an important role in treatment of infections caused by Candida spp. and Aspergillus spp. in immunocompromised children. However, there are no population pharmacokinetic models of the echinocandins for pediatric patients. The safety and descriptive pharmacokinetics of micafungin in children were recently reported. However, a population pharmacokinetic model in children is needed in order to accurately determine the dosage of micafungin that produces an equivalent magnitude of drug exposure to that observed in adults. In order to explore the effect of weight on micafungin pharmacokinetics, a standard two-compartment pharmacokinetic model, a linear model, and an allometric power model were developed. For all three models, the fit to the data was excellent, with comparable measures of precision and bias. However, the superior log-likelihood value of the allometric power model suggested that it best reflected the data and was therefore chosen for a more detailed analysis of the magnitude and pattern of drug exposure which develop following the administration of micafungin. The allometric power model suggested that clearance in smaller children is higher than that predicted on the basis of weight alone. Consequently, a degree of dosage increase is required in smaller children to ensure comparable levels of drug exposure to those observed in larger children and adults. The allometric power model developed in this study enables identification of pediatric dosage regimens of micafungin which, based upon Monte Carlo simulations, result in equivalent drug exposures to those observed in adults, for which antifungal efficacy has been established.

The pharmacokinetics and safety of micafungin, a novel echinocandin, in premature infants

BACKGROUND

: Candidal fungal infection rates in neonates are increasing and are a significant cause of mortality, especially in low birth weight infants. Micafungin is an echinocandin that works by inhibiting 1,3-beta-D-glucan synthase, an enzyme responsible for fungal cell wall synthesis. The objective of this study was to determine the safety and pharmacokinetics of micafungin in premature infants.

METHODS

: This was a phase I, single-dose, multicenter, open-label, sequential-dose trial of intravenous micafungin investigating 3 doses (0.75 mg/kg, 1.5 mg/kg and 3.0 mg/kg) in 18 premature infants weighing >1000 g (n = 6 in each dosage group). A further 5 infants (500-1000 g) were enrolled in the 0.75 mg/kg dosage group only.

RESULTS

: The mean +/- standard deviation gestational age in the >1000 g dosage group was 26.4 +/- 2.4 weeks and, on entry, patients had one or more of a variety of underlying conditions, including sepsis, pneumonia and other infections caused by Candida or other species. Micafungin pharmacokinetics in preterm infants appears linear. However, premature infants >1000 g on average displayed a shorter half-life (8 hours) and a more rapid rate of clearance (approximately 39 mL/h per kg) compared with published data in older children and adults. All doses of micafungin were well tolerated and no serious drug-related adverse events were observed.

CONCLUSIONS

: Single doses of micafungin, ranging up to 3.0 mg/kg, appear well tolerated in premature infants weighing >1000 g. The drug's elimination half-life and total plasma clearance in preterm infants appear dissimilar to published values for these parameters in older children and adults. The reason(s) for this apparent difference remain to be investigated.

Micafungin (FK463), alone or in combination with other systemic antifungal agents, for the treatment of acute invasive aspergillosis

BACKGROUND

Micafungin (FK463) is a new lipopeptide compound (echinocandin) with activity against Aspergillus and Candida species. This study evaluated the safety and efficacy of micafungin in patients with proven or probable invasive aspergillosis (IA).

METHODS

A multinational, non-comparative study was conducted to examine proven or probable (pulmonary only) Aspergillus species infection in a wide variety of patient populations. The study employed an open-label design utilizing micafungin alone or in combination with another systemic antifungal agent. Criteria for IA and therapeutic responses were judged by an independent panel.

RESULTS

Of the 331 patients enrolled, only 225 met diagnostic criteria for IA as determined by the independent panel and received at least one dose of micafungin. Patients included 98/225 who had undergone hematopoietic stem cell transplantation (HSCT) (88/98 allogeneic), 48 with graft versus host disease (GVHD), and 83/225 who had received chemotherapy for hematologic malignancy. A favorable response rate at the end of therapy was seen in 35.6% (80/225) of patients. Of those only treated with micafungin, favorable responses were seen in 6/12 (50%) of the primary and 9/22 (40.9%) of the salvage therapy group, with corresponding numbers in the combination treatment groups of 5/17 (29.4%) and 60/174 (34.5%) of the primary and salvage treatment groups, respectively. Of the 326 micafungin-treated patients, 183 (56.1%) died during therapy or in the 6-week follow-up phase; 107 (58.5%) deaths were attributable to IA.

CONCLUSIONS

Micafungin as primary or salvage therapy proved efficacious and safe in high-risk patients with IA, although patient numbers are small in the micafungin-only groups.

International, open-label, noncomparative, clinical trial of micafungin alone and in combination for treatment of newly diagnosed and refractory candidemia

Candida spp. are the fourth leading cause of bloodstream infections, and non-albicans species are increasing in importance. Micafungin is a new echinocandin antifungal agent with excellent in vitro activity against Candida spp. Pediatric, neonatal, and adult patients with new or refractory candidemia were enrolled into this open-label, noncomparative, international study. The initial dose of micafungin was 50 mg/d (1 mg/kg for patients <40 kg) for infections due to C. albicans and 100 mg/d (2 mg/kg for patients <40 kg) for infections due to other species. Dose escalation was allowed. Maximum length of therapy was 42 days. A total of 126 patients were evaluable (received at least five doses of micafungin). Success (complete or partial response) was seen in 83.3% patients overall. Success rates for treatment of infections caused by the most common Candida spp. were as follows: C. albicans 85.1%, C. glabrata 93.8%, C. parapsilosis 86.4%, and C. tropicalis 83.3%. Serious adverse events related to micafungin were uncommon. Micafungin shows promise as a safe and effective agent for the treatment of newly diagnosed and refractory cases of candidemia. Large-scale, randomized, controlled trials are warranted.

Safety, tolerability, and pharmacokinetics of Micafungin (FK463) in febrile neutropenic pediatric patients

Micafungin (FK463) is a new parenteral echinocandin. A multicenter, phase I, open-label, sequential-group dose escalation study was conducted to assess the safety, tolerability, and pharmacokinetics of micafungin in neutropenic pediatric patients. A total of 77 patients stratified by age (2 to 12 and 13 to 17 years) received micafungin. Therapy was initiated at 0.5 mg/kg per day and escalated to higher dose levels of 1.0, 1.5, 2.0, 3.0, and 4.0 mg/kg per day. Micafungin was administered within 24 h of initiating broad-spectrum antibacterial antibiotics for the new onset of fever and neutropenia. The most common overall adverse events in the study population were diarrhea (19.5%), epistaxis (18.2%), abdominal pain (16.9%), and headache (16.9%). Nine patients (12%) experienced adverse events considered by the investigator to be possibly related to the study drug. The most common related events were diarrhea, vomiting, and headache, all occurring in two patients each. There was no evidence of a dose-limiting toxicity as defined within the prespecified criteria of this clinical protocol. There was one death during the study due to septic shock. The pharmacokinetic profiles for micafungin over the 0.5- to 4.0-mg/kg dose range demonstrated dose linearity. Clearance, volume of distribution, and half-life remained relatively constant over the dose range and did not change with repeated administration. The overall plasma pharmacokinetic profile was similar to that observed in adults. However, there was an inverse relation between age and clearance. For patients 2 to 8 years old, clearance was approximately 1.35 times that of patients >/=9 years of age. In summary, micafungin over a dosage range between 0.5 and 4.0 mg/kg/day in 77 febrile neutropenic pediatric patients displayed linear pharmacokinetics and increased clearance as a function of decreasing age.

Pharmacokinetics, excretion, and mass balance of liposomal amphotericin B (AmBisome) and amphotericin B deoxycholate in humans

The pharmacokinetics, excretion, and mass balance of liposomal amphotericin B (AmBisome) (liposomal AMB) and the conventional formulation, AMB deoxycholate (AMB-DOC), were compared in a phase IV, open-label, parallel study in healthy volunteers. After a single 2-h infusion of 2 mg of liposomal AMB/kg of body weight or 0.6 mg of AMB-DOC/kg, plasma, urine, and feces were collected for 168 h. The concentrations of AMB were determined by liquid chromatography tandem mass spectrometry (plasma, urine, feces) or high-performance liquid chromatography (HPLC) (plasma). Infusion-related side effects similar to those reported in patients, including nausea and back pain, were observed in both groups. Both formulations had triphasic plasma profiles with long terminal half-lives (liposomal AMB, 152 +/- 116 h; AMB-DOC, 127 +/- 30 h), but plasma concentrations were higher (P < 0.01) after administration of liposomal AMB (maximum concentration of drug in serum [C(max)], 22.9 +/- 10 microg/ml) than those of AMB-DOC (Cmax, 1.4 +/- 0.2 microg/ml). Liposomal AMB had a central compartment volume close to that of plasma (50 +/- 19 ml/kg) and a volume of distribution at steady state (Vss) (774 +/- 550 ml/kg) smaller than the Vss of AMB-DOC (1,807 +/- 239 ml/kg) (P < 0.01). Total clearances were similar (approximately 10 ml hr(-1) kg(-1)), but renal and fecal clearances of liposomal AMB were 10-fold lower than those of AMB-DOC (P < 0.01). Two-thirds of the AMB-DOC was excreted unchanged in the urine (20.6%) and feces (42.5%) with >90% accounted for in mass balance calculations at 1 week, suggesting that metabolism plays at most a minor role in AMB elimination. In contrast, <10% of the liposomal AMB was excreted unchanged. No metabolites were observed by HPLC or mass spectrometry. In comparison to AMB-DOC, liposomal AMB produced higher plasma exposures and lower volumes of distribution and markedly decreased the excretion of unchanged drug in urine and feces. Thus, liposomal AMB significantly alters the excretion and mass balance of AMB. The ability of liposomes to sequester drugs in circulating liposomes and within deep tissue compartments may account for these differences.

Plasma protein binding of amphotericin B and pharmacokinetics of bound versus unbound amphotericin B after administration of intravenous liposomal amphotericin B (AmBisome) and amphotericin B deoxycholate

Unilamellar liposomal amphotericin B (AmBisome) (liposomal AMB) reduces the toxicity of this antifungal drug. The unique composition of liposomal AMB stabilizes the liposomes, producing higher sustained drug levels in plasma and reducing renal and hepatic excretion. When liposomes release their drug payload, unbound, protein-bound, and liposomal drug pools may exist simultaneously in the body. To determine the amounts of drug in these pools, we developed a procedure to measure unbound AMB in human plasma by ultrafiltration and then used it to characterize AMB binding in vitro and to assess the pharmacokinetics of nonliposomal pools of AMB in a phase IV study of liposomal AMB and AMB deoxycholate in healthy subjects. We confirmed that AMB is highly bound (>95%) in human plasma and showed that both human serum albumin and alpha(1)-acid glycoprotein contribute to this binding. AMB binding exhibited an unusual concentration dependence in plasma: the percentage of bound drug increased as the AMB concentration increased. This was attributed to the low solubility of AMB in plasma, which limits the unbound drug concentration to <1 microg/ml. Subjects given 2 mg of liposomal AMB/kg of body weight had lower exposures (as measured by the maximum concentration of drug in serum and the area under the concentration-time curve) to both unbound and nonliposomal drug than those receiving 0.6 mg of AMB deoxycholate/kg. Most of the AMB in plasma remained liposome associated (97% at 4 h, 55% at 168 h) after liposomal AMB administration, so that unbound drug concentrations remained at <25 ng/ml in all liposomal AMB-treated subjects. Although liposomal AMB markedly reduces the total urinary and fecal recoveries of AMB, urinary and fecal clearances based on unbound AMB were similar (94 to 121 ml h(-1) kg(-1)) for both formulations. Unbound drug urinary clearances were equal to the glomerular filtration rate, and tubular transit rates were <16% of the urinary excretion rate, suggesting that net filtration of unbound drug, with little secretion or reabsorption, is the mechanism of renal clearance for both conventional and liposomal AMB in humans. Unbound drug fecal clearances were also similar for the two formulations. Thus, liposomal AMB increases total AMB concentrations while decreasing unbound AMB concentrations in plasma as a result of sequestration of the drug in long-circulating liposomes.

Safety, tolerance, and pharmacokinetics of high-dose liposomal amphotericin B (AmBisome) in patients infected with Aspergillus species and other filamentous fungi: maximum tolerated dose study

We conducted a phase I-II study of the safety, tolerance, and plasma pharmacokinetics of liposomal amphotericin B (L-AMB; AmBisome) in order to determine its maximally tolerated dosage (MTD) in patients with infections due to Aspergillus spp. and other filamentous fungi. Dosage cohorts consisted of 7.5, 10.0, 12.5, and 15.0 mg/kg of body weight/day; a total of 44 patients were enrolled, of which 21 had a proven or probable infection (13 aspergillosis, 5 zygomycosis, 3 fusariosis). The MTD of L-AMB was at least 15 mg/kg/day. Infusion-related reactions of fever occurred in 8 (19%) and chills and/or rigors occurred in 5 (12%) of 43 patients. Three patients developed a syndrome of substernal chest tightness, dyspnea, and flank pain, which was relieved by diphenhydramine. Serum creatinine increased two times above baseline in 32% of the patients, but this was not dose related. Hepatotoxicity developed in one patient. Steady-state plasma pharmacokinetics were achieved by day 7. The maximum concentration of drug in plasma (C(max)) of L-AMB in the dosage cohorts of 7.5, 10.0, 12.5, and 15.0 mg/kg/day changed to 76, 120, 116, and 105 microg/ml, respectively, and the mean area under the concentration-time curve at 24 h (AUC(24)) changed to 692, 1,062, 860, and 554 microg x h/ml, respectively, while mean CL changed to 23, 18, 16, and 25 ml/h/kg, respectively. These data indicate that L-AMB follows dose-related changes in disposition processing (e.g., clearance) at dosages of >or=7.5 mg/kg/day. Because several extremely ill patients had early death, success was determined for both the modified intent-to-treat and evaluable (7 days of therapy) populations. Response rates (defined as complete response and partial response) were similar for proven and probable infections. Response and stabilization, respectively, were achieved in 36 and 16% of the patients in the modified intent-to-treat population (n = 43) and in 52 and 13% of the patients in the 7-day evaluable population (n = 31). These findings indicate that L-AMB at dosages as high as 15 mg/kg/day follows nonlinear saturation-like kinetics, is well tolerated, and can provide effective therapy for aspergillosis and other filamentous fungal infections.

Pharmacokinetics, excretion, and mass balance of 14C after administration of 14C-cholesterol-labeled AmBisome to healthy volunteers

Amphotericin B (AmB) in small unilamellar liposomes (AmBisome) provides higher plasma concentrations and greater safety than the conventional deoxycholate formulation. The authors compared the disposition of the liposome's drug and cholesterol components by measuring AmB and radioactivity in plasma, urine, and feces for 1 week after a single 2-hour infusion of 14C-cholesterol-labeled AmBisome (2 mg/kg, 1 microgCi/kg) in healthy adults (4 males, 1 female). The plasma profile of 14C-cholesterol differed from that of AmB, lacking an initial rapid disappearance phase, having a lower total clearance, and having a volume of distribution (0.13 L/kg) close to that of the plasma compartment. The biphasic disappearance and long plasma half-life (147 h) of 14C-cholesterol were similar to those of other low-clearance liposomes. This and the low clearance of 14C-cholesterol from the plasma compartment suggest that it served as a liposome marker. The plasma drug-lipid ratio fell during the study, showing that AmB was cleared from plasma more rapidly than cholesterol or liposomes and suggesting that the composition of the liposomes changed over time. 14C-radioactivity was recovered mainly in the feces (9.5% of dose), consistent with the catabolism of cholesterol to bile salts. Combined fecal and renal clearances were < 18% of total clearance, suggesting that most of the liposomal drug and lipid remained in the body 1 week after dosing. Thus, AmBisome remains in the circulation for an extended period of time while releasing AmB, resulting in its markedly altered pharmacokinetic and safety profiles.

Tacrolimus vs. cyclosporine immunosuppression: results in advanced-stage disease compared with historical controls treated exclusively with cyclosporine

A phase HI comparative trial of tacrolimus- vs. cyclosporine-based graft-vs.-host disease (GVHD) prophylaxis for human leukocyte antigen (HLA)-identical sibling bone marrow transplantation showed less GVHD but poorer survival in the tacrolimus arm. To test the comparability of the two treatment arms with respect to baseline survival prognosis, a matched control study using exclusively cyclosporine-treated patients from the International Bone Marrow Transplant Registry (IBMTR) database was performed. Controls were matched (2:1) based on age (within 5 years), disease, and pretransplant disease status. Two-year survival for tacrolimus-treated clinical trial patients was similar to that of their cyclosporine-treated matched controls (27 and 24%, respectively), and 2-year survival of the cyclosporine-treated clinical trial patients was similar to that of their cyclosporine-treated matched IBMTR controls (42 and 45%, respectively). Consistent with the clinical trial results, the cyclosporine-treated IBMTR controls matched to the tacrolimus group had significantly poorer 2-year survival than the cyclosporine-treated IBMTR controls matched to the cyclosporine group (24 and 45%, respectively; p < 0.01). No significant difference was seen in GVHD between the cyclosporine-treated clinical trial patients and their matched controls; however, the tacrolimus-treated clinical trial patients had significantly less GVHD than their cyclosporine-treated IBMTR controls (p < 0.01). These results support the hypothesis that the survival difference in the phase III trial resulted from an imbalance in the underlying risk factors for death in the two groups rather than from the randomized immunosuppressive regimen.

Phase III study comparing methotrexate and tacrolimus (prograf, FK506) with methotrexate and cyclosporine for graft-versus-host disease prophylaxis after HLA-identical sibling bone marrow transplantation

We report the results of a phase III open-label, randomized, multicenter trial comparing tacrolimus/methotrexate to cyclosporine/methotrexate for graft-versus-host disease (GVHD) prophylaxis after HLA-identical sibling marrow transplantation in patients with hematologic malignancy. The primary objective of this study was to compare the incidence of moderate to severe (grade II-IV) acute GVHD. Secondary objectives were to compare the relapse rate, disease-free survival, overall survival, and the incidence of chronic GVHD. Patients were stratified according to age (<40 v >/=40) and for male recipients of a marrow graft from an alloimmunized female. There was a significantly greater proportion of patients with advanced disease randomized to tacrolimus arm (P = . 02). The incidence of grade II-IV acute GVHD was significantly lower in patients who received tacrolimus than patients in the cyclosporine group (31.9% and 44.4%, respectively; P = .01). The incidence of grade III-IV acute GVHD was similar, 17.1% in cyclosporine group and 13.3% in the tacrolimus group. There was no difference in the incidence of chronic GVHD between the tacrolimus and the cyclosporine group (55.9% and 49.4%, respectively; P = .8). However, there was a significantly higher proportion of patients in the cyclosporine group who had clinical extensive chronic GVHD (P = . 03). The relapse rates of the two groups were similar. The patients in the cyclosporine arm had a significantly better 2-year disease-free survival and overall survival than patients in the tacrolimus arm, 50.4% versus 40.5% (P = .01) and 57.2% versus 46.9% (P = .02), respectively. The significant difference in the overall and disease-free survival was largely the result of the patients with advanced disease, 24.8% with tacrolimus versus 41.7% with cyclosporine (P = .006) and 20.4% with tacrolimus versus 28% with cyclosporine (P = .007), respectively. There was a higher frequency of deaths from regimen-related toxicity in patients with advanced disease who received tacrolimus. There was no difference in the disease-free and overall survival in patients with nonadvanced disease. These results show the superiority of tacrolimus/methotrexate over cyclosporine/methotrexate in the prevention of grade II-IV acute GVHD with no difference in disease-free or overall survival in patients with nonadvanced disease. The survival disadvantage in advanced disease patients receiving tacrolimus warrants further investigation.

Fluconazole versus amphotericin B in the treatment of esophageal candidiasis in cancer patients

Thirty-one patients with malignancy and endoscopy-confirmed symptomatic esophageal candidiasis were randomly assigned to receive oral fluconazole, 200 mg once daily, or intravenous amphotericin B, 0.3 mg/kg, over 1-4 weeks. Clinical efficacy was determined weekly and follow-up esophageal endoscopy with biopsy and culture performed whenever possible. Both agents produced rapid resolution of symptoms, especially dysphagia and odynophagia. All 13 evaluable patients in the fluconazole group and 10/12 treated with amphotericin had clinical improvement. Endoscopy showed eradication of the fungus in all 11 patients undergoing repeat endoscopy, with cure or improvement of esophagitis. The incidence of adverse effects attributable to treatment was higher in the amphotericin group. The efficacy of oral fluconazole in esophageal candidiasis appears to be equivalent to that of amphotericin, with fewer adverse reactions.

Fluconazole prophylaxis of fungal infections in patients with acute leukemia. Results of a randomized placebo-controlled, double-blind, multicenter trial

OBJECTIVE

To evaluate the efficacy and safety of fluconazole for prevention of fungal infections.

DESIGN

A randomized, placebo-controlled, double-blind, multicenter trial.

PATIENTS

Adults (257) undergoing chemotherapy for acute leukemia.

INTERVENTION

Patients were randomly assigned to receive either fluconazole (400 mg orally once daily or 200 mg intravenously every 12 hours) or placebo. The study drug was started at initiation of chemotherapy and continued until recovery of neutrophil count, development of proven or suspected invasive fungal infection, or the occurrence of a drug-related toxicity.

MEASUREMENTS

Fungal colonization, proven superficial or invasive fungal infection, empiric antifungal therapy with amphotericin B, drug-related side effects, and mortality.

MAIN RESULTS

Fluconazole decreased fungal colonization (83 of 122 [68%] placebo patients compared with 34 of 119 [29%] fluconazole patients colonized at end of prophylaxis, P < 0.001) and proven fungal infections (27 of 132 [21%] placebo patients compared with 11 of 123 [9%] fluconazole patients infected, P = 0.02). Superficial fungal infections occurred in 20 of 132 (15%) placebo patients but in only 7 of 123 (6%) fluconazole patients (P = 0.01), whereas invasive fungal infections developed in 10 of 132 (8%) placebo patients and in 5 of 123 (4%) fluconazole patients (P = 0.3). Fluconazole was especially effective in eliminating colonization and infection by Candida species other than Candida krusei (66 of 122 [64%] placebo patients colonized at end of prophylaxis compared with 11 of 119 [9%] fluconazole patients, P < 0.001; 22 of 132 [17%] placebo patients infected compared with 7 of 123 [6%] fluconazole patients, P = 0.005). Aspergillus infections were infrequent in both fluconazole (3 cases) and placebo groups (3 cases). The use of amphotericin B, the incidence of drug-related side effects, and overall mortality were similar in both study groups.

CONCLUSION

Prophylactic fluconazole prevents colonization and superficial infections by Candida species other than Candida krusei in patients undergoing chemotherapy for acute leukemia and is well tolerated. Fluconazole could not be clearly shown to be effective for preventing invasive fungal infections, reducing the use of amphotericin B, or decreasing the number of deaths.

Potential hazards of selenium as a chemopreventive agent

Clinical and metabolic features of the trace element selenium and the full spectrum of its animal and human toxicity have been reviewed. The difficulties in coming to an easy understanding of the biologic properties of selenium stem from its multiple forms and complex metabolic and biochemical pathways. It is suggested that chemoprevention trials focus on the efficacy of organic and inorganic prototype forms such as selenomethionine and the selenite ion. While some appreciation of the toxic potential of these two prototype forms can be predicted from existing information, additional formal toxicology will be necessary, particularly for selenomethionine.

Clinical Oncology Program: a community cancer control model

The majority of cancer patients are diagnosed and treated in their local communities, making it imperative to upgrade cancer management at the community level. The Clinical Oncology Program has demonstrated that sophisticated cancer control programs are possible in a community setting. Moreover, if "quality of survival" data collection is included in such programs, valuable information emerges that can further improve cancer management in the community.

Viral reverse transcriptase suppression associated with erythroid differentiation of Friend leukemia cells

The Friend erythroleukemia cell line T3-C12, which produces Friend murine leukemia virus (F-MuLV) and can be induced to synthesize hemoglobin by dimethyl sulfoxide (DMSO), was monitored for viral RNA-dependent DNA polymerase reverse transcriptase (RT) activity. The amount of viral 60-70S RNA released from DMSO-treated cells was unaffected or increased compared to that from control cells, while RT activity from treated cells was decreased. Accordingly, the specific activity in F-MuLV from DMSO-treated cells expressed as RT/70S RNA was decreased to 8% of the control activity. The 5-bromo-2'-deoxyuridine added to cultures containing DMSO reversed the differentiation process, and the F-MuLV thus treated did not exhibit the reduced RT activity normally observed in DMSO-treated virus. Cell-free F-MuLV incubated with and without DMSO showed the same RT activity, indicating that DMSO itself did not inhibit RT activity. However, when F-MuLV-containing pellets from control and DMSO-treated culture fluids were mixed, there was marked inhibition of the control RT activity, suggesting that RNase hybrid activity was stimulated or that an inhibitor was produced. Assays of F-MuLV-RNase hybrid released from control and DMSO-treated cells showed no difference in activity, indicating that a specific inhibitor of RT was produced or activated. Additions of certain nucleotide triphosphates to RT incubation mixtures did not result in any stimulation of RT activity in DMSO-treated F-MuLV, suggesting that phosphatase was not responsible for the observed inhibition. The results suggested that DMSO treatment of T3-C12 cells caused a reduction in viral RT activity by stimulating the production of an inhibitor, the nature of which is unknown.

Cell cycle and morphological changes during growth and differentiation of a rat basophilic leukemia cell line

Cells of the rat basophilic leukemia cell line RBL-1 differentiated maximally when permitted to achieve growth arrest in a high-density stationary phase, in which the cell number is constant, and the cells are arrested in a G phase of the cycle. Features of differentiation are the accumulation of large basophilic granules and increases in membrane receptors for immunoglobulin E. However, changes in histamine content did not parallel granule development or changes in immunoglobulin receptor concentration. During rapid "forced exponential" growth, the cell number doubles every 8 hr, 50% of the cells are in S phase, and differentiation is minimal.

Insulin binding of acute lymphocytic leukemia cells

Because of differences in insulin binding of cultured lymphoic cell lines, T- and B-cell surface receptor and 125I-insulin binding studies were performed on the bone marrow and peripheral blood leukocytes of 13 children with active acute lymphocytec leukemia. Based on surface receptors, nine patients had null-cell disease and four had T-cell disease. The mean per cent insulin binding of the bone marrow cells from the null-cell patients was 10.0% +/- 8.1 and from the T-cell patients was 0.18% +/- 0.13. The mean insulin binding of the cell suspensions of the peripheral blood from the null-cell patients was 7.3% +/- 7.5 and 0.07% +/- 0.06 from the T-cell patients. Displacement studies with nonradioactive insulin indicated that null leukemic cells bore specific binding sites. These results indicated that there may be metabolic as well as surface membrane heterogeneity among the acute lymphocytic leukemias of childhood.

Erythroid differentiation in cultured Friend leukemia cells treated with metabolic inhibitors

The induction of erythroid differentiation in the T3-C12 clone of Friend leukemia cells by dimethyl sulfoxide is accompanied by reduction in viral RNA-dependent DNA polymerase activity with increased cellular delta-aminolevulinic acid synthetase activity and hemoglobin synthesis. These cells were treated with a variety of compounds to determine whether other durgs are capable on inducing erythroid differentiation. While several hormones, inhibitors of RNA synthesis, organic solvents, inhibitors of DNA polymerase, sulfhydryl inhibitors, and inducers of delta-aminolevulinic acid synthetase administered singly did not stimulate hemoglobin synthesis like dimethyl sulfoxide, inhibitors of DNA and RNA synthesis such as adriamycin, mitomycin C, and hydroxyurea:mithramycin were synergistic in stimulating erythroid differentiation.

Cell cycle-associated changes in receptors for IgE during growth and differentiation of a rat basophilic leukemia cell line

The rat basophilic leukemia cell line (RBL-1) showed an inverse relationship between growth rate and expression of receptor activity for IgE. After prolonged exponential growth, the number of receptors per cell stabilized at 4-6 times 10-5. Cells in stationary cultures, which are arrested in the G1 phase of the cell cycle, continued to accumulate up to 0.9-1.7 times 10-6 receptors/cell with no increase in volume. Upon resuspension in fresh medium at low density, these cells were shown to lose up to 70% of the receptor activity within 4 h. Assessment of cultures synchronized by double thymidine block and cells fractionated by centrifugation of a Ficoll gradient indicated that the RBL-1 cells acquire receptors in the G1 phase of the cell cycle. No accumulation of active receptors occurred during the S and G2 phases, though the average cell volume increased. Cell division resulted in a drop in number of receptors per cell while the number of cell-bound receptors in the culture remained unchanged. This indicates that during mitosis receptors were simply distributed to daughter cells.

Insulin-dependent regulation of insulin receptor concentrations: a direct demonstration in cell culture

Chronic (5-16 hr) exposure of cultured human lymphocytes to 10(-8) M insulin at 37 degrees in vitro produced a decrease in insulin receptor concentrations unaccounted for by simple occupancy of sites; acute exposure (0-2 hr) was without effect. These results reproduced observations in vivo where chronic hyperinsulinemia (e.g., 10(-8) M insulin in the circulation of obese insulinresistant hyperglycemic mice) is associated with a substantial reduction in the concentration of insulin receptors per cell, while acute hyperinsulinemia in vivo has no effect on receptor concentration. These data suggest a reciprocal relationship between insulin in the extracellular fluid and the concentration of insulin receptors per cell, which is mediated at the target cell itself by intracellular insulin-sensitive regulatory processes and directly affects target-cell sensitivity to hormone.

Cytotoxicity Mediated by Human Lymphocyte-Dependent Antibody in a Rapid Assay with Adherent Target Cells

A rapid in vitro assay for lymphocyte-dependent antibody (LDA)-mediated cytotoxicity against adherent target cells has been characterized. Adherent HeLa and human melanoma cell lines were labeled with 51Cr, coated with sera from patients who had received multiple whole blood transfusions, and incubated for 4 hr with human peripheral blood lymphocytes from normal donors. Significant lysis was detected as early as 20 min after incubation with rapid progression in the reaction during the next several hours. Morphologically, the early phase of the reaction was characterized by adherence of lymphocytes to LDA-coated cells. Cytotoxic activity was proportional to LDA concentration, attacking cell concentration, and incubation time. LDA-mediated cytotoxicity was blocked by anti-IgG, supporting the concept that this factor is an antibody. LDA-coated target cells were killed by lymphocytes but not by adherent peripheral blood cells or tissue culture lymphoid cells. Conventional complement did not play a role in target cell destruction because carrageenan, a C1 inhibitor, was included in the reactions and serum samples were heat-inactivated before use. This rapid in vitro assay will prove useful in distinguishing between cytotoxicity resulting from lymphocyte-dependent antibody and other types of cell-mediated cytotoxicity.

Separation of human lymphoid cells into G 1 , S, and G 2 cell cycle populations by use of a velocity sedimentation technique

Human lymphoid tissue culture cells can be separated according to cell size and corresponding cell cycle phase with a velocity sedimentation centrifugation method employing a continuous 5-20% wt/wt Ficoll gradient. A 7-fold increase in streaming limit was achieved by placing a buffer zone of isosmolar 5% Ficoll on top of the gradient before application of the cell load. The various pooled populations of cells from upper, middle, and lower areas of the gradient were characterized using autoradiographic, TCA-precipitable (3)H]thymidine incorporation, and Fuelgen microspectrophotometric methods. The upper range of the gradient contains cells in the G(1) cell cycle phase; the lower range, cells in the G(2) phase; cells found in the middle of the gradient belong largely to the S phase of the cell cycle. These gradient-separated cell pools contained relatively little contamination with cells from other phases of the cell cycle and, when explanted from the gradient into fresh growth media, showed growth patterns characteristic of synchronized cell populations. This system of cell separation provides a useful tool for investigating the relationship of the cell cycle to surface membrane and metabolic characteristics in human lymphoid cell culture systems.

Water-soluble insulin receptors from human lymphocytes

Specific insulin receptors from human lymphocytes in culture have been prepared in aqueous solution without use of detergents or related compounds. Receptors prepared in this fashion exhibit characteristics identical to those reported in intact cells.

Limited periods of gene expression in immunoglobulin-synthesizing cells

In synchronized human lymphoid cell lines, production of immunoglobulins G and M is greatest during the late Gl and S phases of the cell cycle. Little immunoglobulin appears immediately before, during, and immediately after mitosis. The results indicate that transcription of immunoglobulin genes takes place during a limited part of the mitotic cycle.

Biosynthetic and structural studies of a heavy chain disease protein

A new heavy chain disease protein ((gamma)HCD-JM) has been characterized by antigenic and structural criteria. The protein belongs to the IgG3-subclass and is closely related to Fc-fragment of G3-immunoglobulins. The predominant N-terminal amino acid of this protein is glutamic acid in the uncyclized form, and that of another (gamma)HCD is glycine. Studies of the N-terminal peptides indicate that the N-terminal portion of the (gamma)3-heavy polypeptide chain is absent from the (gamma)HCD-JM. These findings rule out a process of normal heavy chain initiation and a large deletion of the Fd region as being responsible for these two heavy chain disease proteins. The (gamma)HCD-JM is a secretory product of cells from bone marrow as shown by studies of in vitro incorporation of amino acids-(14)C. Bone marrow and lymph node have a population of lymphoplasmacytic cells which by immunofluorescence contain (gamma)-heavy chain antigens in the absence of light chain antigens.